Abrading machine



Oct. 27, 1953 H. N. SEYFERTH ABRADING MACHINE 7 Sheets-Sheet 1 FiledOct. 10, 1950 I N VEN TOR. Ha r0 2d h. fifyferth Oct 27,1953 H. N.SEYFERTH ABRADING MACHINE 7 Sheets-Sheet 2 Filed Oct. 10, 1950 INVENTOR.Harold )7. \S yferth 1 WWI 4f;

Oct. 27, 1953 H. N. SEYFERTH.

ABRADING MACHINE 7 Sheets-Sheet 3 Filed Oct. 10, 1950 \M D V \N lnuentarHamid l7. S cyferth (2% Q ""52 8.

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Oct. 2"], 1953 H. SEYFERTH 2,656,651

, ABRADING MACHINE Filed Oct. 10, 1950 7 Sheets-Sheet 4 HIH IIIIIIIIIIII 1 INVENTUR. Harold D. .S ferih M. y ,M/W

Oct. 27, 1953 H. N. SEYFERTH 2,656,651

ABRADING momma Filed Oct. 10, 1950 7 Sheets-Sheet 5 INVENTQ Hamid I7. yfh Oct. 27, 1953 Filed Oct. 10, 1950 H. N. SEYFERTH ABRADING MACHINE 7Sheets-Sheet 6 Oct. 27, 1953 H. N. SEYFERTH ABRADINC MACHINE 7Sheets-Sheet 7 Filed Oct. 10, 1950 Patentecl Oct. 27, 1953 ABRADINGMACHINE Harold N. Seyferth, East Detroit, Mich., assignor to Ex-Cell-OCorporation, Detroit, Mich., a corporation of Michigan ApplicationOctober 10, 1950, Serial No. 189,372

13 Claims. 1

The invention relates to machines for finishing workpieces havingcomplex curves surfaces, and it is more particularly concerned withmachines in which the finishing is effected by the abrasive action of atool on the workpieces.

The machine of the present invention, while capable of finishingworkpieces of a wide variety of shapes, is particularly well adapted forfinishing turbine blades that have been previously machined to thedesired shape and approximately the finished dimensions by a machinesuch as that disclosed in my copending application Serial No. 189,371,filed October 10, 1950. In the machine referred to, the blade is shapedby taking a series of closely spaced longitudinal cuts with the spacingof the tool and work controlled by cam means so as to generate thedesired surface contour.

The primary object of the present invention is to provide a machine bywhich the tool marks and excess stock left on the workpiece in theshaping operation can be removed quickly and efficiently to produce afinished turbine blade precisely dimensioned and smoothly finished.

Another object is to provide an improved turbine blade finishing machinewhich reduces loading unloading time, as well as operating time, thusenabling the blades to be produced quickly and at minimum cost.

Still another object is to provide a machine for finishing curvedsurface workpieces arranged to employ a novel cam having a surface ofrevolution completely free of abrupt rises or falls and capable of beingproduced easily and cheaply from a master pattern, exhibiting thesurface to be reproduced.

A further object is to provide controls for machines of the abovegeneral character which renders their operation substantially automatic.

Qther objects and advantages of the inventionwill become apparent fromthe following detailed description of the preferred embodimentillustrated in the accompanying drawings, in

g which:

Figure l is a perspective view of a machine embodying the features ofthe invention.

Fig. 2 is a perspective view of a typical article adapted to be finishedby the machine, the article being a turbine blade.

Fig. 3 is a sectional view taken in a vertical Fig. 5 is a fragmentaryelevational view of the machine as viewed from the left end.

Fig. 6 is a fragmentary plan view of the outer end of the work holdingspindle and the controls associated therewith.

Fig. 7 is a fragmentary elevational view of the machine as viewed fromthe right end.

Fig. 8 is a sectional view taken in offset planes substantially on theline 8--8 of Fig. 7.

Fig. 9 is a sectional view taken in a vertical plane substantially onthe line 9--9 of Fig. 7.

Fig. 10 is a diagrammatic view showing the relative positioning of thetool and workpiece.

Fig. 11 is a schematic diagram of the hydraulic circuit of the machine.

Fig. 12 is a schematic diagram of the elec trical circuit of themachine.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and willdescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, but intend to cover all modifications and alternativeconstructions and uses falling within the plane through the axis of thework holding spindle and showing the tool slide in elevation.

Fig. 4 is a sectional View of the work supporting frame with the toolslide, the work holding spindle and associated elements showndiagrammatically.

in the appended claims.

Referring to Figs. 1, 3 and 5 of the drawings, the exemplary machinecomprises a generally rectangular box-like base 20 from which rises anupright frame including a pair of end members 2| and 22 joined adjacenttheir upper ends by an inwardly offset vertically disposed web 23.Extending between the end members below the web is an inclined apron 24which serves to direct metal chips and liquid coolant through an opening25 in the top wall of the base 20 into a compartment or sump within thebase.

Supported on the machine frame at the front thereof is a tool spindleand drive assembly 26. This assembly may be of conventional constructionand, as shown more clearly in Fig. 3, comprises a base member 21 boltedor otherwise suitably secured to the web 23 of the frame. The basemember2! is formed with suitable ways for supporting and guiding a slide 28.at the upper end of which is journaled a rotary spindle 29 whichprojects at one side of the slide and carries a suitable abrasive tool,in. this instance a grinding wheel 30; Also mounted on the slide 25 is amotor M arranged to rotate the spindle 29 at high speed through themedium of a driving belt 3!. As shown in Fig. 1, the belt and associatedrotating elements are enclosed in a coolant and chip-proof guard 32.

While as indicated above the exemplary machine is shown equipped with arotary grinding wheel, it will be appreciated that other types ofabrasive tools such as abrasive belts or the like may be employed ifdesired. When equipped with the type of tool illustrated, the spindleand drive assembly 26 is mounted so that the slide 28 is adjustable inan inclined-but generally ver tical path for varying the effectiveheight ofthe. wheel 3%. The spindle 29, in this instance, is arrangedtransversely of the path of adjustment: so that its axis is inintersecting right angularly disposed planes, one of which is verticaland the other inclined to the horizontal. The-wheel 3,0.- 15% mounted atthe upper end of; this. spindle; in a.

position so as to tangentially engage the surface of the work andthrough adjustments of the slide. compensation may be made for tool-s ofdifferent diameter.

Adjustment of the spindle slide 28 is effected in the present instanceby means of a feed screw (not shown) adapted to be rotated. by a hand.wheel 34 located adjacent the lower edgeof the basemember 2i oralternatively by a handwheel. 35 located adjacent one side of the basemem -.v her. As shown in Fig. 3.. the spindle and drive assemblyisequipped with a wheel truing. dresser 38 which may be similar to thatdisclosed in the patent to Gilbert D. Stewart, No. 2,351,159, issued.June 13, 1944. Mechanism similar to that disclosed ha the patentto M. A.Mathys, No. 2,310,977, issued February 16, 1943, may be provided forautomatically adjusting the position of the grinding wheel after eachtruing action. As the dresser and adjusting mechanism form, no. part ofthe present invention, it is not believed necessary to describe. them indetail, but. referonce may be had to the above noted patents for adescription. of their construction and mode of operation.

For supporting a workpiece W in operative. relation tothe grinding wheel30, an. auxiliary frame 49 is mounted at the top. of the machine framefor oscillating or pivotal movement about a horizontal axis and forlinear translation along said axis. Provision is made for holding theworkpiece abovethe wheel 30 so that they pivotal; movements of the frameMl are effective to. move the. work toward or from the wheel and thusdetermine the depth of. cut, that is, the amount of stock removed by thewheel. Rotation of th workpiece together with the traverse movements ofthe frame serve to present the entire work surface to the action of thewheel. To enable the machine to remove surface irregularities andexcessmaterial from the workpiece and produce a finished piece ofprecisely the desired dimensions, provision is -madefr rocking the frameon itspivot to vary the relative positions of the tool and work in timedrelation to. the rotation of the workpiece and its linear translationwith the frame. v 7

Referring to. Fig. 2 of the drawings, the turbine blade W illustrated istypical of the type. of work that can be finished by the machine of thein-- vention. It has a transversely disposed root portion 4| shaped formounting in a dovetailed slot and a blade portion 42 which is convex onone side and concave on the opposite side. The blade portionconventionally has relatively sharp leading and trailing edges and itmay be twisted about its longitudinal axis to present a generally spiralconfiguration. V

For machining purposes, the blade is initially formed with an integrallug 43 at the tip end and this lug center drilled for the accommodati n0f a tail center which assists in accurately locating and supporting theblade during the machining process. The lug and the adjacent unfinishedportion of the blade is cut off at a later stage of the manufacturingprocess.

Referring now to Figs. 3-5 of the drawings, the auxiliary frame 49comprises an elongated top member 45* having depending flanges 4B and4'! at opposite ends. Support for the frame is provided by bearings 48and 49 seated in the legs 46 and .41 and respectively engaging overopposite ends of an elongated rod 50. The rod 50 extends axially.through acylinder 5| formed in a bracket 52, rigidly. supported on therear portion of the machine frame. A piston 53 is fixed to theintermediateportion of the rod 50 within the cylinder. The opposite endsof the cylinder are closed by heads 54 apertured for the passage of theprojecting ends of the rod so that the piston may be; shifted back and.forthwithin the cylinder by introductionof. pressure fluid alternatelyinto 0 p posite ends of the cylinder. At least one of the bearings. 48,49 is confined against movement axially of the rod 5.9 so that theauxiliary frame 40 is constrained to, reciprocate with the rod.

Thebearings 48. and 49 in addition to afford ing an operative connectionbetween the piston rod 56, and the auxiliary frame 40, also. serve asvtrunnion bearings permitting the frame to pivot about the axis of theyrod. Preferably this axis is located adjacent therear edge of theauxiliary frame so that the weight of the frame tends to rock itsforward portion downwardly or toward the tool spindle 29 which itoverlies.

Referring now to Fig. 3 of. the drawings, it will be notedv that adepending flange or web 55 is. provided on the underside of the topmember 45 in parallel spaced relation to the end flange 46. These twoflanges provide support for a rotatable worl; holding spindle Elidisposed with its axis parallel to. and offset forwardly from thepivotal axis of theauxiliary frame.

In the exemplary machine the spindle is formed. at its inner end with anenlarged head 6|. iournaled in a bearing 62 seated in the flange 5 5,The other end of the spindle extends through a sleeve, member 6.3.journaled in a suitable bearing seated in the flange 46.

The head portion 6! of the spindle is formed with an axial recess 91socket 6 adapted to receive the shank portion of a chuck 65 which may belocked in place as by a set. screw 66. The chuck 65 may be, of theconventional type having oppdsfid, jaws operable. to grip or release awork-, piece. Actuation of the jaws is effected through the medium of a.rod 6] extending through an axial bore in. th ndle and roj ct at h outerend thereof. A knob 68 on the projecting end is available formanipulation of the chuck. .In the particular embodiment of theinvention i1.lustrated,v the Work ol g p d is 1 rotatably coupled withthe sleeve 53 as by a feather key 1'0 permitting relative axial move:ment of the parts. A coil spring H interposed between a shoulder '12 onthe spindle and an opposed shoulder on the sleeve member urges thespindle to the right as viewed in Fig 3.

The axial positioning of the spindle is deter.- mined by an annular camit supported on the outer side of the flange 46 coaxially of the spindle60 and having an axially facing bearing surface 14. This surface forms atrack for a follower roller 15 journaled on a stud l6 projecting radieally from a collar Tl rigidly fixed to the spindle.

With this arrangement the spindle is adjusted axially incident to itsrotation as determined by the contour of the cam track 14.

In loading the workpiece W into the machine the root portion 4| isgripped in the jaws of the chuck 65. For supporting the other end of theworkpiece there is provided a tailstock 88 having a center 8| engageablewith the lug 43. The tailstock 80 may be similar in construction to thatshown in my copending application above referred to. For presentpurposes it is sufficient to note that the center 8| is carried by aslide 82 supported for movement axially toward and from the workpiece.The slide may be shifted manually as by a hand lever 84 (Fig. 3) or by apressure fluid operated actuator including a piston 85 operating in acylinder 86 formed within the bracket 83.

To regulate the position of the work relative to the tool 30, that is,the radial distance of the peripheral or operating surface of the toolwith reference to the axis of the workpiece, as the work is rotated andshifted axially relative to the tool, cam means is provided for rockingthe frame 40 about its pivotal axis. The cam means includes a barreltype cam 90 having a surface of revolution 9| generated in conformitywith a master pattern so as to represent the finished contour of theworkpiece. Cam 90 is formed with an axial bore 92 adapted to slidablyreceive the work holding spindle 60 and is nonrotatably secured in fixedangular relation to the spindle by a dowel pin 93 carried by a collar 94keyed to the spindle. A nut 95 threaded on the spindle and bearingagainst the end of the cam 90 remote from the collar 94 holds the camsecurely against the collar and against axial movement relative to thespindle.

For cooperation with the cam 90 a follower roller 96 is mounted on themachine frame directly below the cam. As shown in Fig. 3, the followerroller is supported for rotation about an axis parallel to the axis ofthe work holding spindle adjacent the upper end of a slide 9! supportedand guided in a bracket 98 bolted or otherwise rigidly secured to theframe member 2| of the machine. Provision is made for adjusting thevertical position of the follower roller as required for tools ofdifferent diameters. For this purpose a stop screw 980. (Fig. 4)threaded into the lower end of the slide 91 has its head positioned toengage a shoulder or abutment 99 formed on the bracket 89. The screw maybe provided with a hand wheel I for convenience of manipulation.

Power actuated means is provided fors'ffif'ting the slide 91 andfollower roller 96 upwardly to raise the work supporting frame to aretracted position for convenience of loading and unloading the work.This power means also serves to control the rate at which the frame 40is lowered to feed the workpiece to the tool. As shown in Figs. 3, ,4and 11, the power actuated slide shifting means comprises a piston l0!working in a vertically disposed cylinder I02 formed in the bracket 98below the abutment 89. The piston has a rod I03 projecting'from theupper end of the cylinder and operatively secured in a suitable mannerto the lower end of the adjusting screw 98. Introduction of pressurefluid into one or the other end of the cylinder 182' will .70accordingly raise or lower the frame 48 by pivotsented to the tool.

6 the preceding operation. As the tool marks left by the millingoperation extend longitudinally of the workpiece the preferred relativetraverse is effected by rotation of the workpiece about its longitudinalaxis. Provision is therefore made for for rotating the work holdingspindle to effect such relative traverse while the work is shiftedaxially as by linear traverse of the frame 40 to present successiveareas of the workpiece for the action of the tool. In practice these twomovements are coordinated so that the tool, in effect, describes aspiral path around the work extending from one end to the other of thesurface area to be finished.

Rotation of the spindle 60 is effected in the present instance by amotor MI supported at one end of the frame 40. As shown in Fig. 5, agear I04 on the motor shaft meshes with a pinion I eyed to a shaft I06.The shaft is journaled in a housing I01 which encloses the spindlesupporting sleeve 53. As shown in Figs. 3 and 4, a worm I08 on the shaftcooperates with a worm wheel I 06 keyed to the sleeve 63 to complete thedriving connection.

Preferably the motor MI is a. variable speed motor capable of drivingthe shaft I08 at at least two different speeds. For example, whenoperating on relatively flat surfaces it is desirable to traverse thework relatively slowly past the tool, whereas a much faster traverse isdesirable when the narrow edge of the workpiece is pre- Motor speed maybe conveniently controlled by a control device such as a two positionswitch LS4 actuated in timed relation with the rotation of the spindle68. For actuating the switch LS4 a control member or disk H0 (Figs. 4and 5) is keyed or otherwise nonrotatably fixed on the projecting end ofthe spindle 60. Arcuate shoes I09 supported on the outer face of thedisk H8 engage the switch to close switch contacts LS4A for operatingthe motor at high speed. When the shoes are rotated out of engagementwith the switch, contacts apart as shown in Fig. 5.

The invention also provides novel control 'mechanism whereby complicatedcurved areas such, for example, as the fillet F joining the root portion4! and blade portion 42 of the blade may be finished with greatprecision. The peculiar tool and work movements required for suchfinishing will be appreciated when it is considered that the fillet inaddition to following the general contour of the blade. portion, alsofollows the transverse alinement of the root portion. To impart themovements to the workpiece so as to engage the work and tool along thispath, there is provided a work frame positioning cam H5 whichsupplements the spindle positioning action of the cam 13.

The cam H5 which is generally wedge shaped is interposed between anabutment or anvil H5 mounted on the flange 4I of the frame land a stopelement H1 mounted onan upstanding bracket H8 rigid with the machineframe. As shown in Fig. 8, the face of the cam engaging the anvil H6 isflat while the opposite face is contoured to provide an inclined area IHi, a sub *Staintially flat dwell area I20, 2. second inclined area IIIand another flat dwell area I22.

the frame 40 is urged to the right this cam surface engages the stopwhich thus determines the limit position of the frame. As the cam iswithdrawn, the frame is allowed to advance slowly to the right and thenis maintained in this position for an interval of sufficient length topermit a complete revolution of the workpiece. A further advance occursas the inclined area IZI rides over the stop and there is a furtherdwell as the area -I22 engages the stop. This latter dwell is preferablyalso of suflicient length to permit a complete revolution of theworkpiece. The movements of the table occasioned by the cam IIS combinedwith the axial shifting of the work holding spindle 60 by-the caml3-enable the tool to follow and accurately finish the fillet F entirelyaround the blade.

For retracting the cam I I in the manner above described, there isprovided a pressure fluid operated actuator comprising in this instancea cylinder I23 supported on the flange 41 adjacent one end of the cam. Apiston I24 working in the cylinder has a piston rod I25 formed at itsouter end with a T-shaped head I26 engageable with a T slot I21 in theadjacent end of the cam. By introduction of pressure fluid into one endor the other of the cylinder I23 the cam may be shifted in eitherdirection as required. The supply of pressure fluid is controlled by asolenoid operated valve VI with which is associated a metering valve MVZas shown in Fig. 11.

The pressure fluid operated actuators hereinbefore referred to areincorporated in a novel hydraulic system including suitable controlvalves and electrical operating and control devices for effectingoperation of the machine in a completely automatic cycle. Pressure fluidfor operating the actuators is supplied by a pump P driven by anelectric motor M2. As shown in Fig. 11, the pump draws fluid from a sumpor reservoir R by way of an intake conduit I30 and discharges it by wayof a working pressure relief valve PRV to a branched pressure line I3 I.The pressure fluid is distributed to the various actuators under thecontrol of valves whose operation can be best'described in conjunctionwith a de-- scription of the electrical control circuits shown in Fig.12 ofthe drawings. This control system ispreferably operated at lowvoltage, operating current being obtained in this instance from astep-down transformer T having its primary winding connected across twoof the leads of a three wire power line L which supplies current to themotors M, MI, M2 and M3. A switch S is provided in the power line L forshutting off all power to the machine when desired.

. MRI-2 to connect motor M across the line L.

Assuming that the machine is in a rest condition, thework supportingframe will be at its right-hand limit position with the frame raised 'tounloading position 'through the action of'the actuator for the followerroller slide 91. The workpiece is accordingly loaded in the machine byplacing the root portion in the chuck 65 and closing the chuck jaws byoperation of the knob 68. Cycle selector switch CS is set manually inthe automatic position in which it is shown in Fig. 12 with its upperset of switch contacts CS-I open and its lower set of switch contactsCS-2 closed. Direction control DS switch is now set in its rightposition opening switch contacts DS-I and closing contacts DS-Z.

Limit switch LSI is actuated as a result of the preceding movement tostarting position so that switch contacts LSI--A open and switchcontacts LSI-B are closed. Limit switch LS2 is held open by engagementtherewith of a pin I32 cammed by the control disk III] and LS3 is heldopen by a stop member I33 fixed to the piston rod 50 (Fig. 4). Limitswitch LS4 is engaged by one of the shoes III on the disk IID closingswitch LSl-A and opening switch LS I-B. Limitswitch LS5 has" its switchcontacts LSEi-A open and switch contacts LS5-B closed due to the switchactuator I34 being in a raised position. This actuator is carriedon'anextension I35 of the lower end of the work frame camming piston II.

I An automatic cycle may'now be initiated by momentary closure of cyclestart switch (IS-3. Closure of this switch completes an energizingcircuit for control relay CRI which completes a holding circuit foritself by closing switch CRI-I. Switch CRI-Z is closed to completean-en'ergizing circuit for solenoid SV3 which shifts valve V3 to directpressure fluid into the upper end of the cylinder I82. This pressurefluid circuit extends by way of conduit I40 which branches from thepressure line I3I, conduit I4I, valve V3, conduit I42, metering valveMVI and conduit I43 to cylinder I02. Metering valve MVI includes anadjustable orifice member I44 which determines the "rate of flow offluid to the cylinder and. thus the rate of descent of the worksupporting frame Itmay be appropriate to note at this point that whenvalve V3 is shifted to its alternate position by the biasing spring I45,cylinder I02 is connected to the drain I45 by way of the conduit I43 andthrough a check valve I46 in metering valve MVI, conduit I42, valve V3and conduit I41 which is a branch of the drain I45. The metering orificeis thus by-passed so that the upward movement 'of the piston IUI and thework supporting frame is effected at a rapid rate.

Closure of switch CHI-3 completes a circuit by way of limit switehLS4-Afor motor relay MR2 which closes switch MRZ-I to connect the 'LSfi-Binterrupts the circuit' for infeed cam solenoid SV2 and the closure oflimit switch Lsfi -A completes an energizing circuit for outfeed camsolenoid SVI. ,The latter solenoid energi zes and shifts valve VI todirect pressure fluid to the inner end of the cam actuating cylinder IZS'PressurefIuid flow is by way of a'conduit I48 branching'from thepressure line 'I3I, valve 9 VI and conduit I49 extending to the innerend of the cylinder I23.

Fluid exhausted from the opposite end of the cylinder I23 is dischargedby way of a conduit I50, metering valve MV2, conduit II, valve VI andconduit I52 to drain I45. Fluid thus discharged is directed through ametering orifice defined by an adjustable member I53 which restricts therate of flow and thus limits the withdrawal movement of the cam to apredetermined desired speed. The movement of the cam in the oppositedirection is effected at a higher rate by reason of the by-pass aroundthe orifice afforded by the check valve I54.

In finishing the particular workpiece illustrated, the metering valve isset to effect a withdrawal of the cam H5 at a rate such that the stopmember I I7 rides down the inclined surface H9 and engages the dwell Isubstantially as the Work is brought into operative engagement with thetool. The dwell I20 is of sufficient length to permit the work to make acomplete revolution wherein the fillet F is finished with the cam I3cooperating in positioning the work with respect to the spindle. Thestop then rides down the inclined surface I2I and engages the dwell I22which also is of sufficient length to permit a complete revolution ofthe work.

Shortly before the cam H5 is shifted far enough to disengage the stopfrom the dwell I22,

the actuator piston I24 uncovers a port connected by a conduit I55 withdirection valve DV. The plunger of the valve DV is shifted to the leftso as to direct pressure fluid through the conduit I56 to the right endof the cylinder 5I and thus initiate feed of the work supporting frameto the left. The workpiece is therefore traversed longitudinallyrelative to the tool and at the same time is rotated continuously by themotor MI. As described heretofore, the motor speed is regulated inaccordance with the requirements of the particular surface area beingfinished by alternate operations of the limit switches LS4-A and LS4-B.

Fluid flow to the cylinder 5| is by way of the conduit I40, branchconduit I51, valve DV and conduit I56. Fluid is exhausted from the otherend of the cylinder by way of a conduit I 58, metering valve MV3,conduit I59, metering valve MV4, conduit I60, valve DV to drain I45.Metering valves MV3 and MV4 are respectively fitted with adjustableorifice members I6I and I62. In the present setup the orifice member I62is adjusted to provide a relatively slow feed properly coordinated withthe rotative speed of the work to enable the tool to operatively engagethe entire area of the workpiece. Orifice member I6I which is set for asubstantially higher rate of feed has no effect upon the operation ofthe machine in this particular cycle.

Movement of the work frame 40 to the left continues until the toolreaches the end of the surface being finished, at which time limitswitch LSI is actuated to open normally closed contacts LSI-B. Actuationof the limit switch may be efiected in any suitable manner as anincident to the table approaching its limit position as, for example, bymeans of a stop element I65 fixed to the spindle 50, as shown in Fig. 4.With limit switch LS I-B open the next opening of limit switch LS2 bythe pin I32 on disk I I0 as the work is rotated to an unloading positionresults in the deenergization of control relay CRI. Relay CRI openswitch contacts CR I -2 deenergizing solenoid SV3. This permits thevalve V3 to shift under spring actuation to its table raising position,wherein the upper end of the cylinder I02 is connected to drain, thusallowing the piston IOI to raise the table rapidly to the unloadingposition. The opening of switch contacts CHI-3 interrupts the circuitfor either of the motor relays MR2 or MR3 which may be energized at thistime. As a result the work spindle driving motor MI is stopped.

Switch contacts CRI- I are also opened, deenergizing solenoid valve SVI.As the work frame 40 moves upwardly, limit switch LS5 is disengaged fromthe actuator I34 opening switch contacts LSE-A and closing switchcontacts LS5-B. Closure of the latter switch contacts completes anenergizing circuit for solenoid SVZ which shifts valve VI to directpressure fluid to the cylinder I23 to effect inward feed of the cam II5. As previously explained, such inward movement takes place at a rapidrate.

As the cam I I5 approaches its inner limit position, piston I24 opens aport connected by a conduit I66 with the direction valve DV, thusdirecting pressure fluid to the right end of the valve and shifting thevalve plunger into a position to initiate feed of the work supportingframe 40 in the opposite direction or to the right. This movement takesplace at a rapid traverse rate since the fluid flow to the left end ofthe cylinder is by-passed around the orifices I6I and I62 by way of thecheck valves I61 and I68 associated therewith. As the work supportingframe reaches its right limit position, limit switch LSI is actuated bythe stop member I33 to deenergize control relay CRI. Deenergization ofcontrol relay CRI brings the machine to a complete stop with the worksupporting frame in the raised position, so that the work may beunloaded and a new workpiece loaded therein.

At times it may be desirable to provide for rapid traverse movements ofthe work support ing frame 40 in the same direction as the feedmovement. Under such conditions a limit switch LS3 is arranged foractuation by or in response to the movement of the frame to apredetermined position. Closure of switch LS3 energizes a sole.- noidSV4 which shifts a pilot valve PV to operate a valve V4 to its alternateposition. Valve V4 when so operated establishes a bypass around themetering valve MV4 by connecting conduit I59 with conduit I60 by way ofconduits I69 and I10. Upon opening of the switch LS-3 solenoid SV4 isreleased and the pilot valve is returned by a spring to reset valve V4for feed operation.

The control system may be readily changed to adapt the machine to startgrinding at the tailstock end of the workpiece rather than at theheadstock end, as above described. To eifect such operation, theconduits I55 and I65 leading from the cylinder I24 to the directionvalve DV are reversed. Additionally the direction selector switch DS isoperated to the left position, closing switch contacts DS-I and openingswitch con tacts DS-2. The driving motors are started in the mannerheretofore described by closure of the motor switch MS and the cycle isstarted by closure of the cycle starting switch Cid-3. In this case,however, control relay CRI completes its holding circuit by way ofswitch URI-I, direction switch DS-I and a switch TRI closed by a delayedaction relay TR. This relay is energized by closure of a limit switchLSI-A incident to the work supporting frame moving to its left-handlimit position. Operations then proceed in sub stantially the mannerabove described.

The control circuits may also be conditioned for manual control byoperating the cycle control switch CS to its alternate position, closingswitch CS-i and opening switch OS-rZ. When set for manual operationinward movement of the feed control cam H is initiated by closure ofcontrol switch CS4, Outward movement of the cam switch is initiated. byclosure of control switch CS5. Automatic control of the cam is precludedby, the, opening of control switch CS6. Closure of control switch CS1permits the work spindle drive me motor Ml. to be'started and stoppedmanual? 13!. by, closure of a switch CS8. To. permit, such operation, amanually settable. switch is first actua atcd tov the. manual controlposition, closing switch CS5. and opening swi h CS1 The. machine. may.-be. stopped at any time re-. eardless. of the settingof the cycle.selector switches by Opening a normally closed master stop switch SSE.Likewise, the. tool spindle mo r. may. be. stopped by: actuation. of astopswitch SS2; and, when the. machine is set for automatic. operation,the cyclecmay be interrupted at any. time by, opening a. stop. switchSS3. In thelatter instance the cycle may be, restarted at the. point of;interruption by. momentary closure. of. con trol witch CS.3;.

It wili be. apparent from, the foregoing that the, invention, provides.abrading. machine of novel and advantageous character, particularly Wll? adapted; for. finishing, workpieces having complex curved, surfaces,The machine is easy toload, and. unload: and is rapid and eflicientinoperatiOn, Through. the. medium. of the novel operating. and control.systems incorporated in the machine, the manual labor involved inthefinishing. 0f. workpieces such. as turbine blades is practically.eliminated and the time required forfinishing such workpiecesissubstantially-4 reduced. Overall costs ofrsuch. operationsare thusheld; at; a low figure.

I.- claim as my invention;

1-, In a. machine. foi operating on workpieces haying. complexcurvedsurfaces of revolution, in. combination, a base, a slide mountedonsaid base, a driven abrasive tool carried by said slide, aframesupported onsaidbase for pivota-Lmovement about anaxisdisposedat-one side oh-said. tool. and: for-.linear translationalong said axis, worleholding means onsaidframe spaced from its.pivotaliaxisso as topresent-a held work piece to the tool when theframe is rocked-dnone direction to. an operating position, a camsupported-.on. saidlframein axial alinernent' with the workpiece,said-cam. having asurface of-=revolution derived-from a patternexhibiting the contountobereiiroduced; on the workpiece, a cam follower.on said base engageable b3 said cam, said -carn-and. foilower coactingto vary the; position. of: the workpiece relative to said-tool inaccordance with said-contour, means for rotating said worlcholding meansand said; cam in sy n-' chronisr'n, a pressure fluid; operatedactuatoradapted whenjfi uid is supplied thereto to rock; said f rame fromoperating position to retracted position; said frame returning tooperated position by gravity upon exhaustcf'iiu'id from the actuator,valve mechanism controlling the supplyiand, exhaust of fluid toand'fromsaid; actuator, said .mechanis'm vincludinga metering valveoperative to, control the.- exhaust of fluid from the actuatorandtherebyregulate the. speed of movement of the frame; toward operating.-position,

andia checlg. valve. operative, to estabjlish a bye;

p d, eidmeie inavalve and permitrapide 12 movement of the frame towardretracted posi tion. a

2. In a. machine for'operating on workpieces having complex curvedsurfaces of revolution, in combination, a base, a slide mounted on saidbase, a driven abrasive tool carried by said slide, a frame supported onsaid base for pivotal moves ment. about an axis disposed at one side ofsaid tool and for linear translation along said axis, work holding meanson said frame spaced from its pivotal axis so. as to. present a heldworkpiece. to the tool when the. frame is rocked in one direction to anoperating position, a cam supported on said frame in axial alinementwith the workpiece, said cam havin a surface of: revolution derivedfroma. pattern exhibiting the contour to be reproduced on the workpiece, acam follower on said base. ene eeable by said cam, said. cam and followecoaoting to vary he position. f the. w rkp ece. relative to said tool inaccordanc wi h said; con our, means for rotatin said: worl; holdingmeans, and said cam in synchronisrn, power actuated; means fortranslating said: frame so as to traverse the workpiece and, cam axiallyrelative to said tool and said rollower, and control, means inch; ing a.second cam, shiftable. in timed e a ion. to. the. rotation of said work;holding means for oordina ing. the rate; or movement of said frame with,the. liotative Speed aid 1 1 01 11 means 3-. In; a. machine for: nish nworkpieces; hav e ompl x urved surf ce in. combinatiom a. ase, a drivenabras ve. tool upported; on said. base, W011i; supporting means; mountedon. said: base fo mov me a dir ction; to. feed: the.

o k; o. and. tract t. from th tool: and; a. dis m t on t r rerseh wornpast the tool, a.

n atiyc nc dcnt o; he; t tion. o said; pindlfi:

for imparting axial movements to the spindle; a. eco d; am norm l positned o b o k, aid WQii upp r i m ans; ag ins movem nt. by. aid-p wer actutcdlmeans. and: an ctu or-t r;- w ih raW n "d seco d: amifroni;sadzblpclsina ina har dmiper ntroll m i l ment he. work; sucportinsi meanuchiwithclr ali n ma hine o h. Q KQifiGGS.. iWr' om x: urs ssh urfaces;om-binati m. haemadrirenab i e oo supp rted ongsaid. means: m un on;aid: ionto .d-theworkla dr etrac i ti rom h ool -n adircctioir. oraverse tha -enemas. the 0 1;. a work; holdens indle. uppo ed: sa Work.snumrtina; means for rotatiop and; mo h m an r ota ing; aid: p ndles.newer actu t d. an r in ai i work; supnortinsr a d: rayere nadir ction;means;

' o. v hcs otati n of-sai.

limo emcntseto t esn nd cia.

4 ,ca slaeainstmovementby saidi new r: riu ted; eans. pressure fluid:peratedi mea o h ft ng: aid; s condi to; permit:

on ro l d movement f: said; Work; supportin -2 means b i aid p w.actuatedm ans.andicontroli means; cia ed:

for; rewlgtipgjherate;ofwvithdrawal;

a tion of aid: first came. and; therebyon imi ed; axiah more! pindle;

tn saidupressure fluidt-oper-l' 13 cause the tool to describe apredetermined path about the workpiece.

5. In a machine for finishing workpieces having complex curved surfaces,in combination, a driven abrasive tool, work supporting means includinga frame swingable about an axis spaced laterally from said tool and forlinear translation about said axis, a first power actuated means forswinging said frame between operating and retracted positions, rotarycam means for determining the operating position of said frame, a secondpower actuated means for translating said frame and said cam means, a,work holding spindle rotatably supported on said frame, a motor forrotating said spindle and said cam means, and control mechanismincluding control devices for initiating and interrupting the operationof said power actuated means and said motor for effecting in sequencethe swinging of said frame to operating position, rotation of thespindle with the workpiece in operative engagement with the tool,translation of the workpiece relative to the tool, swinging of the frameto retracted position, and translation of said frame back to startingposition.

6. In a machine for finishing workpieces having complex curved surfaces,in combination, a driven abrasive tool, work supporting means includinga frame swingable about an axis spaced laterally from said tool and forlinear translation about said axis, a first power actuated means forswinging said frame between operating and retracted positions, rotarycam means for determining the operating position of said frame, a secondpower actuated means for translating said frame and said cam means, awork holding spindle rotatably supported on said frame, a variable speedmotor for rotating said spindle and said cam means, and controlmechanism including control devices associated with said power actuatedmeans for effecting in sequence the swinging of said frame to operatingposition, rotation of said cam means and said spindle with the workpiecein operative relation with the tool, and translation of the workpieceaxially relative to the tool, said mechanism also including controlmeans for periodically varying the speed of said motor in timed relationto the rotation of said spindle.

'7. In a machine for finishing workpieces having complex curvedsurfaces, in combination, means for supporting a workpiece for movementtoward and from an abrasive tool, cam means controlling the position ofthe workpiece relative to the tool to determine the depth of cut takenby the tool, means for rotating the workpiece and said cam, means forimparting axial movement to the workpiece, and control mechanism foreffecting in sequence rotation of the workpiece in engagement with thetool with the workpiece restrained against axial movement to cause thetool to describe a generally circular path :around the workpiece, andsimultaneous rota- :tion and axial translation of the workpiece to causethe tool to describe a generally spiral path around the workpiece fromone end to the other of the same.

8. A machine as set forth in claim 7 characterized by the provision ofmeans in the control mechanism operative when the tool reaches said"other end of the workpiece to shift the workpiece out of engagementwith the tool and to interrupt its rotation.

9. In a machine for operating on workpieces having complex curvedsurfaces of revolution, in

combination, a base, a slide mounted on said base, a driven abrasivetool carried by said slide, a frame supported on said base for pivotalmovement about an axis disposed at one side of said tool and for lineartranslation along said axis, a work holding spindle on said frame spacedfrom the pivotal axis of the frame so as to present a held workpiece tothe tool when the frame is rocked in one direction to an operatingposition, a cam supported on said frame in axial alinement with thespindle, said cam having a surface of revolution generated from a pattemexhibiting the contour to be reproduced on the workpiece, a cam followeron said base engageable by said cam, said cam and said follower coactingto vary the position of the workpiece relative to said tool inaccordance with said contour, means including a variable speed motor forrotating said spindle and said cam in synchronism, power actuated meansfor translating said frame to traverse the workpiece and cam axiallyrelative to the tool and follower, a pair of electrical switchesoperable selectively to effect operation of said motor at differentspeeds, a disk mounted on and rotatable with said spindle, and switchactuating elements carried by said disk for actuating said electricalswitches at predetermined points in the rotation of said spindle.

10. In a machine for operating on workpieces having complex curvedsurfaces of revolution, in combination, a base, a slide mounted on saidbase, a driven abrasive tool carried by said slide, a frame supported onsaid base for pivotal move-' ment about an axis disposed at one side ofsaid tool and for linear translation along said axis, 'a work holdingspindle on said frame spaced from the pivotal axis of the frame so as topresent a held workpiece to the tool when the frame is rocked in onedirection to an operating position, a cam supported on said frame inaxial alinement with the spindle, said cam having a surface ofrevolution generated from a pattern exhibiting the contour to bereproduced on the workpiece, a cam follower on said base engageable bysaid cam, said cam and said follower coacting to vary the position ofthe workpiece relative to said tool in accordance with said contour,means including a variable, speed motor for rotating said spindle andsaid cam in synchronism, power actuated means for translating said frameto traverse the workpiece and cam axially relative to the tool andfollower, a pair of electrical switches operable selectively to effectoperation of said motor at different speeds, a third electrical switchadapted when. actuated to stop said motor, a disk mounted on androtatable with said spindle, and actuating elements for said switchesmounted on and rotatable with said disk.

11. In a machine for finishing workpieces having complex curvedsurfaces, in combination, a base, a driven abrasive tool supported onsaid base, work supporting means mounted on said base for movement in adirection to feed the work to and retract it from the tool and in adirection to traverse the work past the tool, a work holding

